The Resident Evil 3 DAT format is, as much of the PSX-basedformats, quite simple, but unfriendly and a waste of space.I'm just gonna start with the fomrat itself.

At Offset 4096 (0x1000), there is a kind of 'TOC'. Is simplystarts with a 32Bit Integer telling you how much files there arein this DAT file. After that, the TOC Entries begin:

They are variable-sized, b'cause they use Null-terminated Strings for their filenames. Before the name, there are 2 32Bit Longs, telling you the Offset and the File Length of the File in the DAT Archive. But the Offset is not a 'simple' Offset. You will have to multiply this offset by 8.

That should be all you'll need to read out a DAT File. However,you'll soon see that you've got another problem: the extracted files...

They aren't in their 'real' format, they're encrypted / compressedagain...

So let's take a look at those files, too...

These Files have two 'chunks':

1. some kind of Header 2. The main Data itself

The first 2 Bytes are a 16Bit Integer specifying the length of the 'header'. After this follows another 32Bit Integer tellingyou the length of the main Data. That means:

Unknown2: I really have no idea, what this part is, but it seems to the same in a lot of files ... sometimes 'DeSOca|.' and things like that... I'll just ignore it...

Okay, see that Number of HeaderEntries thingy? This is what tells you,how many entries there are inside of the header:Every Entry consists of 8 Bytes:Directly after that Unknown2 Entry, there are the first 4 Bytes of every Entry. I have no idea what these Values are. They don't seem to be floats,longs or anything else... I just have no idea :(

However, after these values, there are another 4Byte Values, Integers thistime. They seem to divide the RAW data into several pieces. If you take allthese values and add them, then you will have the length of the RAW Data...But this doesn't make any sense after all...

There's a theory I have:------------------------The whole file is stored in the 'RAW' pool. And it's encrypted...That's what I think: The file has been divided into several pieces: That are thoseblocks, whose length is specified by those 4Byte Integers. And the other4Byte Values work as an key for the encryption...Probably that's just trash, but I've got the feelin' that this could bethe way it goes here... oh, and every block may not be greater than 32.768 Bytes...

However, I have done some testing witht these files, and the result is:This encryption is very sensible. CAPCOM did a good work on creating it...

Oh, really? Here is a man called "PmData". He has decrypted Resident Evil 3's files, and he showed background image and skin texture he got. You can register at that forum and login to view the attachments.